We look at Curiosity's safe landing, and what to expect as it is activated.

Last night Curiosity's MAHLI camera sent back its first color image, looking north through its dust cover at the rim of Gale Crater.

Curiosity woke up at about 5:45pm Pacific Time Monday (morning for the rover), on very flat terrain, with no obstacles visible. Even though the vehicle hasn't been fully checked out yet, images and video are now beginning to rain back down to Earth (though NASA's live video streams were still being hammered). If you're wondering what it's all about, here's a quick rundown on Curiosity, its many cameras, its instrumentation, and JPL's initial activity list.

The mission

Curiosity's primary mission is to determine whether Mars has, or has ever had, an environment capable of supporting life. NASA's search for life on the other planets of the solar system has largely shifted from looking for direct evidence to looking for habitability first—is the environment conducive to life and are any of the raw materials present? By studying the rocks and soil of the area around the landing site, the spacecraft can provide some answers to those questions.

Curiosity's generous helping of cameras

Image credit: NASA JPL

Curiosity has a lot of cameras, 17 to be exact:

• Four pairs are redundant front and rear "hazcams" to help deal with navigational hazards as they arise. The first two images sent back were hazcam pictures taken before the dust covers were removed.

• Two pairs are left and right redundant Navcams, black and white cameras set up to give stereo imaging with a 45-degree field of view.

• The left and right MastCams can take true color 1600x1200 images, or 720p video at 10 frames per second. The left camera has a 34mm focal length, which gives a 15-degree field of view. The right camera has a 100mm focal length, which yields a 5.1-degree field of view. Neither camera has a zoom lens, but both have autofocus.

• The Mars Hand Lens Imager (MAHLI) is mounted on a robotic arm and is so named because it's mounted on a boom and can be used like a geologist's hand lens to look closely at samples. The MAHLI camera can resolve objects down to 14.5µm per pixel. It does have zoom, and its focal length can vary from 18.3 to 21.3 mm, with a 33.8- to 38.5-degree field of view. MAHLI is also equipped with its own LED illumination, including ultraviolet LEDs to check for fluorescence.

• The Mars Descent Imager (MARDI) took 1600x1200 color images at about 5 frames/second. It started at about 3.7km altitude and continued all the way down to just before the skycrane began lowering the rover. It has a 70° by 55° field of view, which gave it about a 1.5m/pixel resolution when the descent stage got down to 2km. On the ground, its resolution is about 1.5mm/pixel, with about a 100x75cm field of view, but it will point straight down from about 70cm above the ground.

MARDI recorded video of Curiosity's descent to Mars, which will allow mission planners to find out exactly where Curiosity landed. That video may prove crucial to future mission planning, and it should also be pretty dramatic.

The Chemistry and Camera complex (ChemCam) is really an entire suite of instruments. It includes a 1067nm infrared laser to use for laser-induced breakdown spectroscopy, targeting, and vaporizing rocks. It can then use a small micro-imager camera along with detectors to look simultaneously at the plasma in near-IR, visible, and UV ranges. ChemCam can resolve images down to 1mm at a 10m distance. In addition to the seventeen cameras, Curiosity has several other instruments:

• The Alpha-particle X-ray Spectrometer (APXS) bombards samples with alpha particles and looks at the spectrum of X-rays emitted, yielding the elemental composition of the sample.

• The Chemistry and Mineralogy (CheMin) X-Ray diffraction and X-ray fluorescence instrument, another spectrometer, is aimed toward identification of minerals by mapping their crystalline structure. It x-rays samples and relays emission histograms and diffraction patterns back to Earth for analysis.

• The Radiation Assessment Detector (RAD) was turned on before Curiosity reached Mars and will continue to measure radiation on the surface. The RAD is specifically aimed at aiding planning for a future human mission.

• The Dynamic Albedo of Neutron (DAN) instrument was included to measure hydrogen on the Martian surface, which will yield a better measure of how much water and ice is present near Curiosity's landing site.

How did it all work so well?

The Mars Science Laboratory was developed and built by a team from NASA's Jet Propulsion Laboratory in Pasadena, with help from several contractors and investigators from other countries. The cameras and sensors were built by or with help from other NASA centers, Los Alamos National Labs, Malin Space Science Systems, and scientists or engineers from France, Russia, Canada, Finland, and Spain.

JPL's Mars Science Laboratory team just after MSL's landing on Mars

Photo credit: NASA TV video capture

At first blush, MSL looked to many as if it was far too complex to possibly succeed, but it's beginning to look like the Seven Minutes of Terror video may have been a masterful case of NASA managing the public's unreasonable expectations. NASA's internal prediction of a successful landing was about 98 percent, a number given by its simulations.

That's not to say that the MSL team doesn't deserve every gram of credit they can get; there's nothing remotely easy about landing a spacecraft on a planet 330 million kilometers away. Their response to the successful landing showed how much they had invested in the rover's success.

But throughout most of the mission, Curiosity was actually repeating a relatively tried-and-true mission profile: enter with an aeroshell, slow with a supersonic parachute, slow more with rocket power. The only portion of the descent that was unconventional—and it was completely unconventional—was the "skycrane" at the end.

An image of Curiosity's descent sent back by Mars Reconnaissance Orbiter

Photo credit: NASA JPL

The "skycrane" technique turned out to be very successful. Just over a third of the total fuel remained in the descent stage as it sped away, giving rise to speculation that a future Mars mission could use a descent stage that acts as a science station after it drops its rover off, or one able to drop off multiple rovers. Curiosity has also demonstrated that a very large probe can be landed on the Martian surface, something that will be essential for any future mission to bring a sample back to Earth.

Beyond the skycrane, some of the reasons for the mission's smooth start date back to the design and construction. Many of the parts for modern space probes are now "catalog parts." The US aerospace industry has matured to the point where some parts are used on many spacecraft, and they can be found and ordered by weeding through catalogs. The pieces are very consistent performance-wise and they have been thoroughly tested. That means nobody is off inventing something new in a machine shop.

Perhaps most importantly, NASA JPL has also adopted very stringent software development standards with origins in the automotive industry. Basically, they limit common coding techniques that become too risky when lives or expensive spacecraft hang in the balance.

What happens now?

NASA JPL will spend the next two weeks checking out systems and deploying the cameras. After spending several years and 2.5 billion dollars, they don't want to take any chances.

Color images and data will begin streaming in soon as cameras pass checkout and get activated. The Curiosity team will use them to figure out more exactly where the rover is. They'll correlate images with radar data, and know where the vehicle is within centimeters. And they'll then pick its first destination.

A hazcam image shows Mt. Sharp, taller than any mountain in the lower 48 US states

Photo credit: NASA JPL

JPL has already begun sending lists of commands to the rover. Atop the list was the checkout and deployment of the High-Gain Antenna (HGA). Curiosity has, up until now, been using a relatively weak omnidirectional antenna that does not need to be pointed, but can only transmit data at very low speeds. The HGA will be crucial for transmitting the color video and volumes of data which are coming later. Although the HGA checkout is still in progress, really exciting data began arriving at just after midnight Tuesday morning: weather, radiation data, and camera images.

Many activities are waiting until the onboard software is replaced with a newer, more capable version, a process that will begin on Sol 5 (a sol is a day on Mars). The JPL team has time; Curiosity uses a plutonium-powered radioisotope thermoelectric generator (RTG) power source, good for many years.

Already, though, scientists and non-scientists the world over are studying the images that have been sent back to Earth. The science has already begun.

Many activities are waiting until the onboard software is replaced with a newer, more capable version, a process that will begin on Sol 5 (a sol is a day on Mars).

And here I thought only Bethesda relied on day-one* patches.

Kidding aside, this is seriously cool. I will always regret being born too late to see the moon shot live - my strongest childhood memory of space exploration is the Challenger - but I'm thrilled almost beyond words to see us put rovers on Mars. Here's hoping this translates, somehow, into more funding for NASA - maybe up them to 1% of the federal budget?

Many activities are waiting until the onboard software is replaced with a newer, more capable version, a process that will begin on Sol 5 (a sol is a day on Mars).

And here I thought only Bethesda relied on day-one* patches.

Kidding aside, this is seriously cool. I will always regret being born too late to see the moon shot live - my strongest childhood memory of space exploration is the Challenger - but I'm thrilled almost beyond words to see us put rovers on Mars. Here's hoping this translates, somehow, into more funding for NASA - maybe up them to 1% of the federal budget?

* Or day-five, as the case may be

Man, give NASA a quarter of the DoD budget. USA would still have the largest defense budget, and space would be ours much faster.

Those are pretty high-resolution cameras, and they are collecting all sorts of other information, too.

Dear Ars, a request: I'd love a detailed, technical article about how NASA communicates with this rover, and how the technologies have evolved since Voyager, etc.

First, what frequencies and encoding techniques do they use for the signal to get decent bandwidth and high reliability? Second, what about the protocols? Obviously, standard TCP/IP isn't going to function with 14-minute one-way latency! The options and constraints are very different than terrestrial RF usage, like 802.11a/b/g/n/ab WiFi or even long-wave ham.

I was going to inquire as to this very question myself after reading the comments. From the article:

Quote:

Many activities are waiting until the onboard software is replaced with a newer, more capable version, a process that will begin on Sol 5 (a sol is a day on Mars).

Are they flashing the firmware on this unit or are they updating the software libraries that the system call on for various routines? I'm not a robotics expert so I'm kinda shooting from hip on this. I understand we're dealing with a very good group of experts, and that they've thought of every (hopefully) contingency on this, but this comes across to us regular techs as madness (madness I tell you!!). What exactly are they updating?

If our goal is to prepare for manned missions to Mars, I think the next step should be to correct the problem of inconsistent communications by deploying a communications and GPS constellation around Mars.

The current constellation around Mars provides inconsistent ground relay coverage because of varying orbits. The orbits for the MRO, Express, and Odyssey were all picked for science, not communications and positioning. A small constellation of satellites in more deliberately picked orbits could in concert provide continuous high gain contact.

Thank you Ars for doing an overview of all the cameras on this thing. Can't believe how many people (on other web sites, at least) look at the initial low-res, b&w pics and then rush to comment "billions of dollars and they couldn't put a decent camera on it?"

Those are pretty high-resolution cameras, and they are collecting all sorts of other information, too.

Dear Ars, a request: I'd love a detailed, technical article about how NASA communicates with this rover, and how the technologies have evolved since Voyager, etc.

First, what frequencies and encoding techniques do they use for the signal to get decent bandwidth and high reliability? Second, what about the protocols? Obviously, standard TCP/IP isn't going to function with 14-minute one-way latency! The options and constraints are very different than terrestrial RF usage, like 802.11a/b/g/n/ab WiFi or even long-wave ham.

Really though, in the ten months since launch (over a year since code freeze) they probably made improvements, or added new features.

The ability to flash was, I'm sure, at the top of their list from day zero. The process is likely bulletproof (there are two computers on board, one as a backup, that can probably be used to restore the other if a remote flash fails)

An another articular that would be interesting. How Spirit's and Opportunity's super extend mission affected the design of Curiosity. Both in hardware changes to make them more robust in the long term, to mission planing changes to support the possibility of an order of magnitude increase in the length of survival.

Many activities are waiting until the onboard software is replaced with a newer, more capable version, a process that will begin on Sol 5

My best guess is that they've been working on tweaks and upgrades while waiting for this thing to get to mars. I'm sure they've made improvements, since it's been 9 months since any actual person has been able to touch it.

I'd wager that the software update is not for "new features" - but that this is PR speak for fixing critical bugs that have been discovered in testing and analysis while the rover has been in transit.

I imagine there are many different firmwares on the rovers, with some of them designed to be simple and static - so that there will always be some base level of functionality attached to the radios that can respond to us and do simple things like reboot other components and restore the firmware on another component to the last version if an update fails.

Many activities are waiting until the onboard software is replaced with a newer, more capable version, a process that will begin on Sol 5

My best guess is that they've been working on tweaks and upgrades while waiting for this thing to get to mars. I'm sure they've made improvements, since it's been 9 months since any actual person has been able to touch it.